Brie Larson couldn't help gushing over her boyfriend, Phantom Planet lead singer Alex Greenwald, in an interview backstage after adorably offering up an "I love you" from the 2016 Screen Actors Guild Awards podium on Saturday.

"Oh man, I mean, he's the other half of the equation -- how can you explain support?" she told ET's Cameron Mathison. "I mean, it goes beyond anything. He's just my person, he's my best friend."

While accepting the award for Outstanding Performance by a Female Actor in a Leading Role for Room, cameras cut to Alex in the audience sweetly mouthing the words, "I love you, too" to his lady.

With a laugh, Brie confirmed that she did see the heartwarming gesture from the stage.

"Yeah, we love each other," she gushed.

The 26-year-old also got candid about her heartfelt acceptance speech, in which she confessed that she was "always worried that I was deeply unlovable."

"I was homeschooled, I didn't really feel like I was part of any group, so this is a really big one for me," she explained backstage. "For a movie like this to be responding so well to so many different types of people all over the world shows that these things that I thought were my darkness, that were my own struggles, that were only mine, are actually everybody's. And that makes me feel so relieved and so happy to be a human."